# Calculating Van Der Waals Forces: Gecko Climbing Walls

• Howlin
In summary, the conversation is about the Van Der Waals Force and its relation to a gecko's ability to walk up walls. The person is wondering if there is an equation to calculate this force and has done some research and checked some papers. Another person mentions the Wikipedia page on Van Der Waals Force and suggests checking out some papers as well. The first person thanks them for the information.
Howlin
Hi

Is there an eqauation to work out the Van Der Waals Force between solids?
I am enquiring this in relation to how a gecko is able to walk up a wall.

I have done some research and it says that a gecko can walk up walls because of Van Der Waals forces, I want to know is there an equation to work it out?

Howlin said:
Hi

Is there an eqauation to work out the Van Der Waals Force between solids?
I am enquiring this in relation to how a gecko is able to walk up a wall.

I have done some research and it says that a gecko can walk up walls because of Van Der Waals forces, I want to know is there an equation to work it out?

As another person interested in the exact same thing I'd like to request this too.

Have you checked the papers which report these results? (See here and here.) There's also the "en.wikipedia.org/wiki/Van_der_Waals_force" which may be of interest.

Last edited by a moderator:
Mike H said:
Have you checked the papers which report these results? (See here and here.) There's also the "en.wikipedia.org/wiki/Van_der_Waals_force" which may be of interest.

I'd seen the wiki pages but hadn't seen the papers.
Thanks

Last edited by a moderator:

Hello,

Thank you for your question. Yes, there is an equation that can be used to calculate Van Der Waals forces between solids. It is known as the Hamaker constant and it takes into account the properties of the two materials involved, such as their surface energies and polarizabilities. However, it is important to note that the calculation of Van Der Waals forces is a complex process and involves multiple factors, so the equation may not provide an exact value in all cases.

In the case of gecko climbing walls, the Van Der Waals forces play a crucial role in allowing the gecko's feet to stick to the surface. The tiny hairs on their feet called setae have contact points that create a large surface area for Van Der Waals forces to act upon. This, combined with the gecko's ability to control the adhesion through muscle contractions, allows them to walk on vertical surfaces and even hang upside down.

I hope this helps answer your question. Keep in mind that Van Der Waals forces are just one of the many factors that contribute to the amazing ability of geckos to climb walls.

## 1. How do geckos climb walls using Van Der Waals forces?

Geckos have unique toe pads that are covered in millions of tiny hair-like structures called setae. These setae have even smaller structures called spatulae that create a large surface area for Van Der Waals forces to act upon. When geckos press their toe pads against a surface, the Van Der Waals forces between the setae and the surface create an adhesive bond, allowing them to climb walls and ceilings.

## 2. What is the significance of Van Der Waals forces in gecko climbing?

Van Der Waals forces are essential for geckos to climb walls because they allow the gecko to create a strong bond with the surface without using any adhesives or sticky substances. This allows the gecko to easily detach and reattach its feet as it climbs, and also allows for quick movements and adjustments while climbing.

## 3. How do scientists calculate the strength of Van Der Waals forces in gecko climbing?

Scientists use a mathematical model called the Derjaguin–Muller–Toporov (DMT) model to calculate the strength of Van Der Waals forces in gecko climbing. This model takes into account factors such as the geometry of the setae and spatulae, the surface properties of the climbing surface, and the weight of the gecko to determine the adhesive force.

## 4. Can Van Der Waals forces be artificially replicated for human use?

Yes, scientists have successfully replicated Van Der Waals forces for human use in the form of synthetic adhesives and tapes. These materials mimic the structure of gecko setae and can create strong adhesive bonds without leaving any residue behind. They have potential applications in areas such as robotics, medical devices, and even space exploration.

## 5. Are Van Der Waals forces the only mechanism geckos use to climb walls?

No, Van Der Waals forces are not the only mechanism geckos use to climb walls. They also use a combination of other factors such as friction, suction, and muscle strength. However, Van Der Waals forces play a crucial role in allowing geckos to climb smooth, vertical surfaces with ease and precision.

• Classical Physics
Replies
23
Views
2K
• Introductory Physics Homework Help
Replies
6
Views
2K
• Atomic and Condensed Matter
Replies
8
Views
2K
• Atomic and Condensed Matter
Replies
24
Views
7K
• Chemistry
Replies
1
Views
2K
• Materials and Chemical Engineering
Replies
6
Views
2K
Replies
7
Views
2K
• Chemistry
Replies
4
Views
3K
• Introductory Physics Homework Help
Replies
6
Views
1K