Coasts GI - done

Question 1

State things to note before conducting an investigation.

Answer 1

1. Data collection method
2. Sampling method
3. Collecting sites
4. Time of collection
5. Sample size
6. Sampling frequency
7. Human errors
8. Human activities
9. Who to sample (tourism)

Question 2

State the formula for wave length.

Answer 2

wave length = 1.56 x (wave period)^2

Question 3

State the formula for wave steepness.

Answer 3

Wave height/wave length

Question 4

Describe the process taken to measure wave height.

Answer 4

1. Go into the water, far enough to measure a wave, but close enough for safety (not beyond knee)
2. Place the ruler into the water where it touches the beach floor
3. Measure height of the crest & trough as it passes and mark the top & bottom of the wave on the ruler.
4. Record measurement in the recording sheet
5. Subtract trough from crest, giving wave height.

Question 5

Describe the process taken to measure wave period.

Answer 5

1. Go into the water, far enough to measure a wave, but close enough for safety (not beyond knee)
2. Place the ruler into the water where it touches the beach floor
3. Use stopwatch to time duration for 10 successive crests and troughs (10 complete waves) to pass through
4. Record time taken. Take the time measured divided by 10 waves to get the wave period.
5. Repeat the experiment twice to get 2 wave periods and average them out.

Question 6

State the definition of wave frequency. Describe the process taken to measure wave frequency.

Answer 6

Wave frequency is the number of waves that passes through per unit time (like per min).

1. Go into the water, far enough to measure a wave, but close enough for safety (not beyond knee)
2. Place the ruler into the water where it touches the beach floor
3. Use stopwatch to time duration (5 min) and count the number of waves that break on the shore.
4. Record time and number of breaking waves on recording sheet. Divide the number of waves by 5 mins.
5. Repeat exercise twice, record values each time, and calculate the average timing.

Question 7

Describe the steps taken to measure longshore drift.

Answer 7

1. Find a safe spot where view of the open sea is not blocked.
2. Use a wind vane to find the direction of the wind.
3. Decide on a good distance to measure the longshore drift over (eg. 10m)
4. Lay measuring tape close to the water’s edge on the decided distance and place 2 poles to mark the start and end point.
5. 1 person should go to a small distance before the start line and drop the orange into the water.
6. When the orange passes the start point, the timekeeper should start the stopwatch.
7. When the orange passes the end point, the timekeeper should stop the stopwatch.
8. Record time taken and the pattern the orange travelled.
9. Repeat the process again to get an average value.

Question 8

Describe the steps taken to measure beach profile.

Answer 8

1. Identify line of transect, which is a straight line on the beach perpendicular to shoreline.
2. Put measuring tape along the line of transect. Mark out points on the line of transect.
   - Constant gradient beach: mark out points of equal intervals of 2m
   - Undulating beach: mark out points where there are significant changes in the slope
3. Put a ranging pole at 2 points A & B. Ensure the poles are held straight and do not sink into the sand.
4. Position protractor clinometer on the ranging pole at A and hold steady.
5. The gradient should be measured by people of the same height. Hold the clinometer at eye level and align with the top of the other person’s head.
6. The angle where string crosses scale on the edge of the protractor is the angle of elevation between your eye & the object sighting.
7. Read the angle and record on the recording sheet. Record distance between A & B.
8. Repeat 3-6 to get gradients between the other points marked out.
9. With graph paper, draw a graph with x-axis showing the point of measurement (A-D) and y-axis showing angle
10. Connect the points with straight lines to show gradient.

Question 9

Describe the steps taken to measure cliff height.

Answer 9

1. Stand a safe distance from the cliff, and measure the distance, noting it down.
2. Use a clinometer and look towards the top of the cliff to get the angle of elevation.
3. Height of cliff = (distance from cliff to observer x tan angle) + height of observer

Question 10

Describe the steps taken to perform sediment analysis.

Answer 10

1. Identify the line of transect along the coast.
2. Choose a sampling method for the samples obtained from the line of transect.
3. Collect a fixed weight of sand sample from the line of transect (eg. 200g samples).
4. Repeat identical sample collection (average)
5. Put the samples into an oven to dry the sample and record the mass of the dry samples.
6. Put 1 sample through a sediment sifter that sorts the sediments according to their sizes of 5mm, 2.5mm, 2mm and etc.
7. The larger sediments can be measured with a pair of vernier calipers.
8. Measure the mass of each group of sediment size and record it down.
9. Calculate the mass of the sediment sizes as a percentage of the original mass of the sample.
10. Repeat for all other samples collected and also the 2nd set of sample to average the calculations.

Question 11

Describe the steps taken to measure exposed groyne height.

Answer 11

1. Identify and record the aspect of each side of the groyne (updrift & downdrift)
2. Use meter ruler to measure from the top of the groyne to the surface of the sediments on each side.
3. Take digital pictures to illustrate the differences in sediment levels
4. Repeat for each groyne or use a a suitable sampling method.

Question 12

State some natural factors that may affect data collection.

Answer 12

1. Tidal & wind conditions (especially on different days)
2. Obstructions to floats/waves under the water
3. Presence of swimmers or paddlers