Working scientifically

Question 1

What is an independent variable

Answer 1

The variable which is changed by the investigator (the investigator decides its values for the independent variable)

Question 2

What is dependent variable?

Answer 2

The variable which we measure for every change in the independent variable

Question 3

What is the control variable?

Answer 3

What we keep the same throughout the investigation

Question 4

Why is the control variable important?

Answer 4

We can’t be certain that any changes of the dependent variable are only caused by changes is the independent variable

Question 5

What should you do when describing a practical in exams?

Answer 5

Make sure you identify independent and dependent variables and describe what you would do to keep control variable the same

Question 6

What is an accurate value

Answer 6

One that is close to the true value

Question 7

What is a parallel error

Answer 7

One that is made du to incorrect positioning of eyes while reading on measuring scale e.g eyes not being level either top of coloured liquid of thermometer

Question 8

How can paralex error be overcome?

Answer 8

Using a digital thermometer

Question 9

How can random error occur when timing how long a chemical reaction occurs

Answer 9

Students will have different reaction times and will start and stop clocks at different times

Question 10

When repeating experiments and producing varying results what is this due to?

Answer 10

Random errors

Question 11

How do you reduce the effect of random errors

Answer 11

Repeating experiment

Question 12

What is zero error

Answer 12

When a piece of equipment gives a reading other than zero when it should be zero

Question 13

What is a systematic error

Answer 13

An error that will cause the readings to differ from the true value be a consistent amount each time each measurement is made

Question 14

How do we get rid of systematic errors?

Answer 14

Doing the experiment again using different technique or equipment and compare results to check if systematic error had occured

Question 15

How can we tell the precision of the values?

Answer 15

How tightly clustered the readings are around the mean value and will have a smaller range

Question 16

What does precision not tell us

Answer 16

Whether the measurements are close to the true value e.g if there’s a systematic error

Question 17

What is uncertainty

Answer 17

We can’t be certain of the accurate or true value of any measurement e.g when relying on peoples reaction time to stop and start a timer

Question 18

How can you determine uncertainty

Answer 18

Range of values÷2 (answer will have ± in front of value)

Question 19

What does uncertainty equation tells us?

Answer 19

Where the actual or true value is likely to lie e.g between 1.4 and 1.5

Question 20

What is repeatable results

Answer 20

When an investigator repeats an experiment under the same conditions and gets similar results)

Question 21

What are reproducible measurements

Answer 21

When we have similar results produced by different investigators with different equipment