A lubricant is a substance added between two surfaces to reduce friction.

Friction is the force of one surface gripping or rubbing on another.

A variable is categoric if it comes in distinct, separate categories.

A variable is continuous if it can take any value, including decimals, on a scale of numbers.

A conclusion states what you found out in an experiment and explains how you know.

Reducing friction: analysis

Science

In the Hidden forces unit, they will build on this knowledge to learn about turning forces, forces that hold objects on a surface, and those that make some objects float.

In primary science, pupils learnt that air resistance, water resistance and friction push back against moving objects. 

Forces

A {{}} is any substance added between two surfaces to reduce the friction forces.

graph (usually a bar chart or line graph)

Which part of an experiment write-up states what you found out and explains how you know?

Which of the below is the name for a variable that comes in distinct, separate types or categories?

Wood polish was the best lubricant and hand soap was the worst.

Wood polish was the best lubricant because friction was the lowest.

Hand soap was the best lubricant and wood polish was the worst.

Hand soap was the best lubricant because friction was the highest.

Jun did an experiment to test how far objects slide across a surface lubricated with different lubricants. His results are in the table. Which of the below is a correct conclusion from Jun's results?

Izzy tested how far masses slide with different lubricants. The mass slid 53 cm on cooking oil, 40 cm on washing-up liquid and 33 cm on water. Which is the best bar chart of these results?

A bar chart because 'shape of 100 g mass' is a categoric variable.

A line graph because 'shape of 100 g mass' is a categoric variable.

A bar chart because 'distance travelled' is a continuous variable.

A line graph because 'distance travelled' is a continuous variable.

Laura tested how far different shaped 100 g masses slide across the same surface. Her results are shown in the table. Which option correctly explains what type of graph Laura should draw?

In an experiment, anything that could change (vary) between tests is called a ...

A conclusion should contain the practical steps needed to do an experiment.

A conclusion should contain all the data collected in an experiment.

A conclusion should contain what you found out and explain how you know..

Which option correctly describes what an experiment conclusion should contain?

Which kind of force does a lubricant reduce?

Which one of these variables comes in different categories?

Lubricated moving parts would be smoother and quieter.

Lubricated moving parts would be greasy to touch.

Lubricated moving parts would wear down less over time.

Lubricated moving parts would need less force to keep moving.

Identify the possible benefits of lubricating moving parts of a system, to reduce the friction. 

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